The Oklahoma State Medical Examiner's Office confirms a second fatality as a result of a large tornado which touched down in Shawnee Sunday.

A preliminary estimate from the National Weather Service puts the Shawnee twister at EF 4, which would mean wind speeds of 166 to 200 mph.

It was part of a massive storm system which spawned tornadoes across much of the Midwest, spanning an area from Texas to Minnesota.

At least two large tornadoes touched down in Oklahoma, one in Edmond near Oklahoma City and the deadly twister which created a lot of damage and killed two people in Shawnee.

The ME identifies the men killed as Glen Irish, 79, and Billy Hutchinson, 76, both of Shawnee.

The twister knocked several semi-truck off of the US Highway 277 overpass down onto Interstate 40, leading the OHP to shut the highway down.

A number of buildings were damaged or destroyed.